November 1, 2018 — Agata Blaszczak-Boxe. The net effect of this combination of hydrological events is that Lake Erie’s current water levels are much higher than usual for this time of year. The surface of the Great Lakes region is still in the process of bouncing back from the weight of massive glaciers that began retreating near the end of the last ice age 11,000 years ago. There are 5 sections, one for each lake, that provide a table describing past conditions, a graphic showing monthly and annual average surface water temperatures, and a graphic showing monthly and annual maximum ice cover. Lake Superior water levels are at a new record high. Precipitation increases in winter and spring are consistent with the fact that a warming atmosphere can transport more water vapor. Water levels are measured in relation to elevation reference points, or benchmarks, around the Great Lakes. Runoff to the Great Lakes is typically highest during the spring, when melting snow combines with liquid precipitation, leading to increased streamflow. "Lake Superior has a lot more room to absorb that heat before it starts hitting that upper limit where it starts evaporating. These glaciers and ice sheets, which were miles thick, literally pushed the Earth’s crust into its upper mantle. 955 Oliver Road Runoff shows a large amount of variability in the winter and early spring months, but no clear sign of a trend. However, in 2018 and 2019 the maximum ice cover was slightly above 50%. Current water levels on the Great Lakes are setting records. Thunder Bay, ON. The largest variability in surface water temperatures occurs in July on Lake Superior. In addition to the current onset of record highs, water levels in Lake Erie have been rising earlier in spring and declining earlier in fall. As a result, increased atmospheric moisture contributes to more precipitation during extreme events. Click on the graphic to the right to view the NBS relative to long term average NBS for the past 5 years. "This is a big deal to see these warming trends, and the potential implications, even with all the weird stuff going on around the world in 2020. Innovative techniques, such as incorporating information from snow and soil moisture maps into seasonal water supply forecasts, can help capture a full picture of what is happening to the water budget. He mentioned that as recently as five or six years ago, water levels in the lakes were dangerously low. Net basin supply (NBS) is the primary driver of Great Lakes water levels. Nearshore Marine Forecasts. "When you don't have that wind creating waves and mixing the warm surface water down into the lake, those surfaces can get really hot," he said. As a result, residents on the southern shores are seeing water levels rise very slowly over time. Subscribe to Infosuperior…only #LakeSuperior news. Flooding in New York state along the Lake Ontario shoreline, May 28, 2019. For website corrections, write to lrepao@usace.army.mil. Ironically, long-term geological processes as well as recent heavy precipitation events linked to climate change, threaten even the most “climate-proof” city in the United States. Evaporation during the winter months has shown an increasing trend since the 1950s, but has leveled off in recent years. After very warm surface water temperatures in 2016 during August and September, the last 3 years have been cooler. All NBS graphics will be updated in the spring of each year. Changes in seasonal cycles of snowmelt and runoff align with the fact that spring is coming earlier in a changing climate.